Compressible Elastomeric Spring Railcar Draft Gear
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Solution Overview
Problem
Existing elastomeric springs in railcar draft gear assemblies face challenges in achieving symmetrical compression and equal energy absorption across multiple pads and plate-shaped members, leading to inefficiencies in dynamic impact force management.
Innovation Solution
A compressible elastomeric spring design featuring an elastomeric pad with a solid body, axial abutment, and peripheral lip, mechanically secured to a rigid plate-shaped member, allowing for uniform compression and interlocking with other pads to form a spring stack, utilizing a manufacturing method that includes forming members and axial force application to ensure symmetry and equal compression across the spring stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional attachment methods are used for elastomeric pads to plate members, then the assembly process is simple, but the symmetry and equal compression of pads in the spring stack are compromised
Solution Approach 1:
The attachment mechanism merges the plate member and elastomeric pad into a single integrated unit. The lip of the elastomeric pad is embedded within a groove in the plate member, creating a unified assembly that ensures symmetrical positioning and equal compression across all pads in the spring stack, while eliminating the need for separate attachment components.
Solution Approach 2:
The attachment structure uses a nested configuration where the lip of the elastomeric pad is inserted into and confined by the groove of the plate member. This nesting arrangement provides precise positioning and symmetrical alignment, ensuring that multiple pads compress equally within the spring stack assembly.
2Loss of energy
If multiple elastomeric pads and plate members are arranged serially, then the energy absorption capacity increases, but achieving equal compression of each pad becomes difficult
Solution Approach 1:
The spring stack is segmented into multiple identical units, each consisting of an elastomeric pad integrated with a plate member. The standardized groove-lip attachment design in each segment ensures that all pads have identical geometric constraints and loading conditions, enabling equal compression and energy absorption across the entire serial assembly.
Solution Approach 2:
By merging the plate member and elastomeric pad into an integrated unit through the groove-lip attachment, the design ensures that each pad in the serial stack experiences identical boundary conditions. This integration maintains symmetrical compression across all pads, maximizing the energy absorption capacity of the multi-pad assembly.
3Ease of manufacture
If the elastomeric pad structure is simplified, then the manufacturing process is easier, but the ability to maintain symmetry and equal compression is reduced
Solution Approach 1:
The design combines the elastomeric pad and plate member into a single integrated component through the groove-lip attachment system. This merging eliminates the need for complex separate attachment mechanisms while providing inherent symmetrical positioning, thus achieving both manufacturing simplicity and precision in maintaining pad symmetry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design ensures uniform compression and equal energy dissipation across the spring stack, enhancing the railcar's ability to absorb dynamic impact forces and maintain lateral stability, with the elastomeric pads capable of repetitive absorption and dissipation of forces exceeding 130% of the material's ultimate tensile strength.
Implementation Method 1
an elastomeric pad (408) having a substantially solid body (410) defining a central axis (412) and manufactured from an elastomeric material
Implementation Method 2
for at least absorbing and dissipating energy during operation of a passenger or freight railcar
Data Source
AI summary
A compressible spring includes a substantially solid body defining a central axis and manufactured from an elastomeric material. A substantially solid abutment upstands axially on one end of the substantially solid body. There is also a lip that is disposed on a distal end of the axial abutment in a plane being substantially transverse to the central axis. An axial bore may be provided extending through the thicknesses of the body and abutment. Furthermore, a plate shape member may be provided that is mechanically secured to the substantially solid body during the forming process, wherein the abutment is passed through a central aperture in the rigid member and wherein the lip cages a thickness portion of the rigid member around the central aperture.